iOS-AES128-CBC-No-Padding加密解密.doc

最近的项目中数据传输用到加密，项目选择了AES128 CBC No Padding加密方式，PHP和Android方面的代码网上太多了。但是唯独没有iOS的，但是也有别的写法，但不是是AES128 CBC No Padding或者不是CBC No Padding。自己仿照着写了个，不过PHP端总是解密不出。问题就处在No Padding. No Pading的情况下，一定要对加密数据不是kCCKeySizeAES128倍数部分进行0x0000的填充，不然加密长度不正确，一般情况下选择使用kCCOptionPKCS7Padding（也就是0x0001）进行填充，但是我们是No Padding所以要用0x0000填充。加密后再对加密数据进行了Base64加密，用到了google的GTMBase64，没有的网上自己找，下面上ios的代码： DES3Util.h内容
//
// DES3Util.h
// JuziAnalyticsDemo
//
// Created by wanyakun on 13-6-6.
// Copyright (c) 2013年 The9. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface DES3Util : NSObject

+ (NSString*) AES128Encrypt:(NSString *)plainText;

+ (NSString*) AES128Decrypt:(NSString *)encryptText;

@end
DES3Util.m文件内容
//
// DES3Util.m
// JuziAnalyticsDemo
//
// Created by wanyakun on 13-6-6.
// Copyright (c) 2013年 The9. All rights reserved.
//

#import "DES3Util.h"
#import <CommonCrypto/CommonCryptor.h>
#import "GTMBase64.h"

#define gkey @"16位长度的字符串" //自行修改
#define gIv @"16位长度的字符串" //自行修改

@implementation DES3Util

+(NSString *)AES128Encrypt:(NSString *)plainText
{
char keyPtr[kCCKeySizeAES128+1];
memset(keyPtr, 0, sizeof(keyPtr));
[gkey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

char ivPtr[kCCBlockSizeAES128+1];
memset(ivPtr, 0, sizeof(ivPtr));
[gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

NSData* data = [plainText dataUsingEncoding:NSUTF8StringEncoding];
NSUInteger dataLength = [data length];

int diff = kCCKeySizeAES128 - (dataLength % kCCKeySizeAES128);
int newSize = 0;

if(diff > 0)
{
newSize = dataLength + diff;
}

char dataPtr[newSize];
memcpy(dataPtr, [data bytes], [data length]);
for(int i = 0; i < diff; i++)
{
dataPtr[i + dataLength] = 0x00;
}

size_t bufferSize = newSize + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
memset(buffer, 0, bufferSize);

size_t numBytesCrypted = 0;

CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt,
kCCAlgorithmAES128,
0x0000, //No padding
keyPtr,
kCCKeySizeAES128,
ivPtr,
dataPtr,
sizeof(dataPtr),
buffer,
bufferSize,
&numBytesCrypted);

if (cryptStatus == kCCSuccess) {
NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];
return [GTMBase64 stringByEncodingData:resultData];
}
free(buffer);
return nil;
}

+(NSString *)AES128Decrypt:(NSString *)encryptText
{
char keyPtr[kCCKeySizeAES128 + 1];
memset(keyPtr, 0, sizeof(keyPtr));
[gkey getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

char ivPtr[kCCBlockSizeAES128 + 1];
memset(ivPtr, 0, sizeof(ivPtr));
[gIv getCString:ivPtr maxLength:sizeof(ivPtr) encoding:NSUTF8StringEncoding];

NSData *data = [GTMBase64 decodeData:[encryptText dataUsingEncoding:NSUTF8StringEncoding]];
NSUInteger dataLength = [data length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);

size_t numBytesCrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
kCCAlgorithmAES128,
0x0000,
keyPtr,
kCCBlockSizeAES128,
ivPtr,
[data bytes],
dataLength,
buffer,
bufferSize,
&numBytesCrypted);
if (cryptStatus == kCCSuccess) {
NSData *resultData = [NSData dataWithBytesNoCopy:buffer length:numBytesCrypted];
return [[[NSString alloc] initWithData:resultData encoding:NSUTF8StringEncoding] autorelease];
}
free(buffer);
return nil;
}